Russia's top diplomat says his nation will give the U.N. Security Council evidence that implicates Syria's rebel forces in the Aug. 21 chemical weapons attack near Damascus, the BBC reports.

Word of what Syrian President Bashar Assad's strongest ally on the Security Council plans comes from Foreign Minister Sergei Lavrov.

As the BBC reminds readers, "a U.N. report released on Monday concluded the nerve agent sarin was used in the attack in Damascus, in which hundreds were killed. The U.S. blamed government forces for the attack, but Russia and Damascus have insisted that rebels were responsible."

On that point, The Associated Press adds that "Moscow is insisting that a new United Nations resolution on Syria not allow the use of force, but Russia's foreign minister appeared to suggest Tuesday that the issue could be reconsidered if Syria violates an agreement on abandoning its chemical weapons."